His father was a well-known doctor and had received some notoriety in Christchurch through his involvement with the Styche case.The family had lived in Rangiora until 1896 subsequently moving to Christchurch. Electoral rolls show the family were living at ‘Temple House’ in Madras Street in 1900 and by 1911 they were at 351 Worcester Street.

Montague had been working as a farmhand for H. Jackson, Purau, at the time of his enlistment, and he was recorded in the 1914 electoral roll as being a station manager at Port Levy. He recorded his last address as Redcliffs, and the electoral roll for 1919 shows that his mother, Edith, was living at Clifton, Sumner, with two of his brothers, Oswald and Wilfred, while another brother, John, was recorded as living in Pratt Street, Redcliffs.

Montague enlisted on 19 April 1915 as trooper with Canterbury Squadron, and embarked for overseas service on 14 August 1915 aboard the Tofua to Suez, Egypt. In his service records he is described as being 5 foot 7 ½ inches tall with grey eyes and brown hair. He had a tattoo of a butterfly on his right arm.

Montague served in the Middle East and during his time there had several bouts of hospitalisation for illness and recovery from wounds. He was killed in action in Palestine on 5 November 1917, and was buried at Beersheba War Cemetery, Israel.